Field of the Disclosure
The present disclosure relates to an apparatus for controlling an inverter.
Discussion of the Related Art
An inverter is a power converter that coverts inputted AC (Alternating Current) electric power to DC (Direct Current) electric power, converts the DC electric power to a voltage having magnitude and frequency required by a motor, and output the voltage to the motor.
The conventional inverter operation control is a method to constantly control gap flux in all frequency areas under the base frequency, that is, to control magnetic flux ingredient current of the stator current. The overall current is increased by the effect of voltage drop due to the stator resistance at low velocity. However, the performance is superior to control with only general voltage/frequency relationships, in a case when a large amount of starting torque is required at an initial stage.
However, there are problems in that the method is largely dependent on motor parameters (stator resistance, stator inductance, no-load current), errors occur in the torque boost compensation voltage due to errors in the relevant parameters, and thereby the operation may fail at a large starting torque, in a case when such controlling method is applied to operation of industrial inverters.
In particular, the control of a certain voltage/frequency is to output a voltage corresponding to the frequency required by a predetermined ratio of voltage and frequency. Therefore, there is still a problem in that the operation may fail when a large starting torque is required at low velocity or when there is a large change in load.